This study investigated the effects of organic loading rates on simultaneous carbon and nitrogen removal in an innovative fixed-film aerobic bioreactor. The fixed-film bioreactor (FFB) was composed of a two-compartment aeration tank, in which a synthetic filamentous carrier was submerged as biofilm support media, and a settling tank which polyvinylidene media (Saran) was used as settling aid for suspended solids. Three different organic loading rates, ranging from 0.92-2.02 kg chemical oxygen demand//day were applied by varying hydraulic retention time (HRT). The total soluble organic carbon removal efficiencies were in the range of 90-97%. The removal efficiency of ammonia was found to be in the range of 70-84%. Total nitrogen removal efficiency was found to be in the range of 40-45%, which indicates that denitrification reactions occurred simultaneously in the attached biofilm on the fibrous media in the aeration tank. The settling performance of suspended solids was significantly improved due to the presence of Saran media in the settling compartment, even for a short HRT. The fixed-film aerobic bioreactor used in this study demonstrated efficient treatment efficiency even at higher organic loading rates and at short HRTs.

Kim, M. Y., The effect of dissolved oxygen concentration and internal recycle ratio on the removal of nitrogen and organic compounds in the A/O/O biofilm process, MSc. Thesis, Gwangju Institute of Science and Technology, Gwangju (1997)

13.

American Public Health Association, Greenberg, A. E., Eaton, A. D., Clesceri, L. S., American Water Works Association, and Water Environment Federation, Standard methods for the examination of water and wastewater, 18th ed., APHA-AWWA-WEF, Washington, DC (1992)